The objectives of this research may be summarized as follows: a. To study tyrosinases in the skin of albino animals and hair bulbs of human albinos and elucidate differences between "albino tyrosinase" and that in normally pigmented skin. b. The measurement of tyrosinase in foreskin of newborns and a comparison of the tyrosinase activities in the skin of black and white individuals. c. Mechanistic studies on mammalian and bacterial tyrosinases with emphasis on binding sites of substrates; role of dopa as an intermediate in conversion of tyrosine to dopachrome; and the role of superoxide ion, if any, in tyrosine hydroxylation. d. Isolation of tyrosinase from pigmented mouse skin. e. Study the relation between melanocyte stimulating hormone, tryosinase, and mammalian pigmentation. This would be done by measuring MSH in blood of miniature pigs during pregnancy and lactation and in fetuses and newborns. Tyrosinase would be measured in fetal and newborn skin.